DESCRIPTION: The investigators propose to test the feasibility of developing a method for nuclear medical imaging of thromboembolism with a technetium-99m-labeled CSVTCG peptide fragment of thrombospondin protein, both of which bind to the major platelet glycoprotein, CD36, as further described by their abstract: "With nearly half a million incidences and 200,000 deaths due to deep venous thrombosis (DVT) and pulmonary embolism (PE) in the USA each year, and their enigmatic, non-invasive diagnostic assessment, the need for a Tc-99m agent that can detect DVT or PE promptly and reliably is more dire than ever before. While a large number of radiolabeled monoclonal antibodies, most of them specific for platelet surface glycoprotein IIb- IIIa complex have been investigated, for a variety of reasons none has yet made a significant contribution to the management of these patients. Unlike the three types of peptides, anti-platelet factor IV, DMP 444 and snake venom factors, being investigated as agents to detect PE and DVT, the peptide in question CSVTCG, is the one that exists naturally in the molecular domain of the most endogenous protein, thrombospondin, which takes an active part in the formation of DVT via activated platelets. Also, unlike the other three peptides, CSVTCG binds to major platelets glycoprotein CD 36 (GPIV, GPV). "We have successfully labeled CSVTCG with Tc-99m, examined its biological activity and determined its ability to selectively bind to activated platelets via GP CD 36. We have evaluated Tc-99m-CSVTCG (Tc-99m-TP-1201) to label forming and preformed blood clots in vitro and to detect an experimental DVT in vivo. The results have been highly encouraging and have generated the impetus that has prompted us to undertake this systematic feasibility study that will determine its potential as an agent for scintigraphic imaging of DVT and PE." PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE